Modern breeds of laying hens initiate egg production just prior to twenty weeks of age, and maintain a high level of productivity for an extended period. However, after one year of continuous egg laying (i.e., by approximately seventy weeks of age), hens accumulate considerable body fat and produce eggs at a lower rate and with lower quality shells. For decades, it is known in the art that the rate and quality of eggs produced by laying hens may be rejuvenated by forcing the hens to cease egg production for a period of several weeks. This process, known as “forced molting,” simulates natural molting events in which the hens substantially reduce their feed intake, thereby losing excess body weight, cease egg production, and replace their plumage. When egg production is reinitiated, a higher rate of lay is achieved with improved shell quality.
The most common method of forcing a cessation of egg production in hens is to remove feed for a period of ten to twelve days. Egg production quickly ceases, with body weight losses approximating 25%. While this technique has been highly successful, proponents of animal welfare object not only to the prolonged period of feed deprivation, but also to the 2% to 3% mortality frequently experienced by flocks during the forced molting period. Customer pressure on major egg purchasers has led to stipulations that eggs sold to certain firms not be from force molted flocks. Such pressure is expected to increase.
An alternative to accomplishing hen rejuvenation by complete feed withdrawal has been proposed, whereby flocks are given high fiber feeds with reduced levels of digestible carbohydrate. In such feeds, much of the corn component of the diet is replaced with fibrous feedstuffs such as wheat middlings, a by-product produced during the milling of wheat for flour, and soybean hulls, a by-product of soybean processing for oil and meal production. The objective of such low energy feeds is to reduce the calorie consumption of hens, leading to the desired body weight loss and reduction in egg production. Flock rejuvenation would thus be accomplished without the prolonged feed withdrawal that is of concern to animal welfare groups.
Several studies have been conducted and reported in the scientific literature describing attempts to achieve flock rejuvenation through the use of high fiber and low digestible carbohydrate diets. However, two problems have been observed that compromise the effectiveness of these conventional approaches.
First, hens are able to adjust the amount of feed consumed in accordance with the calorie content of the feed. Thus, when the energy of the feed is reduced, hens partially compensate by consuming greater amounts of feed. This compromises the effectiveness of programs designed to achieve molting without feed withdrawal. Second, very high fiber diets are of a bulky texture, and tend not to flow through modern feed manufacturing and delivery systems. Both problems have limited the success of non-feed withdrawal molting programs.
Therefore, a need exists for an improved reduced calorie feed composition for rejuvenating egg production in laying hens which does not lead to a compensatory increase in the amount of feed consumed, and which may be refined to a relatively small particle size.
In addition to rejuvenating egg production, high fiber feeds are also known to positively affect the health of hens through several potential mechanisms. For instance, dietary fiber affects the structure and function of the gut and may be used to correct intestinal problems, such as ulcers, in hens. Further, feeding hens dietary fiber reduces the potential for diarrhea. Moreover, high fiber feeds speed the elimination of excreta from the hen to assist in digestive cleaning. Accordingly, a need exists for an alternative high fiber feed that may be used to promote the health of laying hens.